Asteroids are rocky and metallic objects that orbit the sun but are too small to be considered planets. They have diverse compositions and shapes, ranging from nearly spherical to very irregular. They are classified based on their composition as determined from spectral analysis and similarities to known meteorites. Asteroids can be found in the asteroid belt between Mars and Jupiter, as well as in near-Earth orbits such as the Amor, Apollo, Aten, and Trojan groups.